Occipital injections for trigemino-autonomic cephalalgias: evidence and uncertainties.

Cluster headache is a debilitating disorder. Oral prophylactic treatments may act with a significant delay, cause side effects, or fail to control the attacks. Injections targeting the occipital nerve have raised interest for the management of CH. Their efficacy is thought to result from the anatomical convergence of trigeminal and cervical afferents in the trigeminal nucleus caudalis. Efficacy and safety of occipital injections are now documented by 2 randomized controlled trials and several case series, though the optimal technique and substance to be injected are still subject to discussion due to varied approaches in the published studies. The evidence supports the use of injected steroids, with or without the addition of an anesthetic. Side effects of local pain are common, but unlikely to be severe. Systemic effects related to steroid absorption are reported but infrequent. Occipital injections provide a rapid benefit on the frequency of attacks and can be used as an adjunct to an oral prophylactic for a quicker improvement. Whether or not this approach can be used without any oral prophylaxis is still to be determined. The technique is easy to master, has a low cost, and should be learned by physicians involved in CH management.